PREDICT(1)                      KD2BD Software                      PREDICT(1)



NNAAMMEE
       predict - Track and predict passes of satellites in Earth orbit


SSYYNNOOPPSSIISS
       predict   [-u   _t_l_e___u_p_d_a_t_e___s_o_u_r_c_e]   [-t   _t_l_e_f_i_l_e]  [-q  _q_t_h_f_i_l_e]  [-a
       _s_e_r_i_a_l___p_o_r_t] [-a1 _s_e_r_i_a_l___p_o_r_t] [-n _n_e_t_w_o_r_k___p_o_r_t]  [-f  _s_a_t___n_a_m_e  _s_t_a_r_t_-
       _i_n_g___d_a_t_e_/_t_i_m_e  _e_n_d_i_n_g___d_a_t_e_/_t_i_m_e]  [-dp _s_a_t___n_a_m_e _s_t_a_r_t_i_n_g___d_a_t_e_/_t_i_m_e _e_n_d_-
       _i_n_g___d_a_t_e_/_t_i_m_e] [-p _s_a_t___n_a_m_e _s_t_a_r_t_i_n_g___d_a_t_e_/_t_i_m_e] [-o  _o_u_t_p_u_t___f_i_l_e]  [-s]
       [-east] [-west] [-north] [-south]


DDEESSCCRRIIPPTTIIOONN
       PPRREEDDIICCTT  is a multi-user satellite tracking and orbital prediction pro-
       gram written under the Linux operating system by  John  A.  Magliacane,
       KD2BD.  PPRREEDDIICCTT is free software. You can redistribute it and/or modify
       it under the terms of the GNU General Public License  as  published  by
       the  Free  Software  Foundation, either version 2 of the License or any
       later version.

       PPRREEDDIICCTT is distributed in the hope that it will be useful, but  WITHOUT
       ANY  WARRANTY,  without even the implied warranty of MERCHANTABILITY or
       FITNESS FOR A PARTICULAR PURPOSE. See the GNU  General  Public  License
       for more details.


FFIIRRSSTT TTIIMMEE UUSSEE
       PPRREEDDIICCTT tracks and predicts passes of satellites based on the geograph-
       ical location of the ground station, the current date and time as  pro-
       vided  by  the  computer system's clock, and Keplerian orbital data for
       the satellites of interest to the ground station. First time  users  of
       PPRREEDDIICCTT  are  provided default ground station location and orbital data
       information files. These files are managed by the program, and are nor-
       mally  located  in  a user's home directory under a hidden subdirectory
       named _._p_r_e_d_i_c_t. First time users will be  prompted  to  supply  PPRREEDDIICCTT
       with their geographical location (the same as selecting option [[GG]] from
       the program's main menu) the first time the program is run. Latitude is
       normally expressed in degrees north with latitudes south of the equator
       expressed in negative  degrees.  Longitude  is  normally  expressed  in
       degrees  west  with  eastern  longitudes expressed in negative degrees.
       This behavior can be modified by passing the _-_e_a_s_t or  _-_s_o_u_t_h  commmand
       line switches to PPRREEDDIICCTT.

       Latitudes  and  longitudes may be either entered in decimal degrees, or
       in degrees, minutes, seconds (DMS) format.  Station altitude is entered
       as  the number of meters the ground station is located above sea level.
       This parameter is not very critical.  If unsure, make a realistic guess
       or simply enter 0.

       Users  of  PPRREEDDIICCTT  need Keplerian orbital data for the satellites they
       wish to track that is preferably no older than one month.  The  default
       orbital  data  supplied with the program is liable to be quite old, and
       so must be brought up to date if accurate results are to  be  expected.
       This  may  be  accomplished by selecting option [[EE]] from PPRREEDDIICCTT''ss main
       menu and manually entering Keplerian data for  each  satellite  in  the
       program's  database,  or  by selecting option [[UU]] and specifying a file
       containing recent 2-line Keplerian element data sets that correspond to
       the  satellites  in  the program's database.  Keplerian orbital data is
       available     from     a     variety     of     sources,      including
       _h_t_t_p_:_/_/_w_w_w_._c_e_l_e_s_t_r_a_k_._c_o_m_/,       _h_t_t_p_:_/_/_w_w_w_._s_p_a_c_e_-_t_r_a_c_k_._o_r_g_/,       and
       _h_t_t_p_:_/_/_w_w_w_._a_m_s_a_t_._o_r_g_/.


PPRROOGGRRAAMM OOPPEERRAATTIIOONN
       The start-up screen of PPRREEDDIICCTT  lists  the  program's  main  functions.
       Several tracking and orbital prediction modes are available, as well as
       several utilities to manage the program's orbital database.


PPRREEDDIICCTTIINNGG SSAATTEELLLLIITTEE PPAASSSSEESS
       Orbital predictions are useful for determining in advance when a satel-
       lite  is  expected  to  come within range of a ground station. They can
       also be used to look back to previous passes  to  help  to  confirm  or
       identify past observations.

       PPRREEDDIICCTT includes two orbital prediction modes to predict any pass above
       a ground station (main menu option [[PP]]), or list only those passes that
       might  be  visible to a ground station through optical means (main menu
       option [[VV]]). In either mode, the user is asked to select a satellite of
       interest  from  a  menu,  and then asked to enter the date and time (in
       UTC) at which prediction calculations should start.

       The current date and time may be selected by default by entering  noth-
       ing  and hitting simply the ENTER key when prompted to enter the start-
       ing date and time.

       Otherwise, the starting date and time should be entered in the form:

            _D_D_M_o_n_Y_Y _H_H_:_M_M_:_S_S

       Entering the time is optional.  If it is omitted,  midnight  (00:00:00)
       is  assumed.   Once complete, orbital calculations are started and pre-
       diction information is displayed on the screen.

       The date and time in UTC, along with the  satellite's  elevation  above
       ground,  azimuth heading, modulo 256 orbital phase, sub-satellite point
       latitude and longitude, slant range between the ground station and  the
       satellite,  and  the  satellite's  orbit  number are all displayed.  If
       spacecraft attitude parameters (ALAT, ALON) are included  in  PPRREEDDIICCTT''ss
       transponder  database  file,  then spacecraft antenna squint angles are
       displayed instead of orbit numbers in the orbital prediction output.

       An asterisk (*) displayed to the right of the orbit  number  or  squint
       angle means the satellite is in sunlight at the date and time listed on
       the line. A plus symbol (+) means the satellite is  in  sunlight  while
       the  ground station is under the cover of darkness at the time and date
       listed.  Under good viewing conditions, large satellites  such  as  the
       International  Space  Station  (ISS), the US Space Shuttles, and Hubble
       Space Telescope, and the Upper Atmosphere Research Satellite (UARS) are
       visible  to  the  naked  eye. If no symbol appears to the right of each
       line, then the satellite is in the Earth's shadow at the time and  date
       listed, and is not receiving any illumination from the sun.

       Pressing  the  EENNTTEERR  key,  the  'YY' key, or the space bar advances the
       orbital predictions to a screen  listing  the  next  available  passes.
       Pressing  the  'LL'  key  allows the currently displayed screen plus any
       subsequent screens to be logged to a text file in your current  working
       directory.  The  name  given  to this file is the name of the satellite
       plus a ".txt" extension.  Any slashes or spaces appearing in the satel-
       lite  name  are replaced by the underscore (_) symbol. The logging fea-
       ture may be toggled on and off at any time by  pressing  the  'LL'  key.
       Exiting  the  orbital  prediction  mode  by pressing 'NN' or hitting the
       EESSCCape key will also close the log file. The log file will be  appended
       with additional information if additional predictions are conducted for
       the same satellite with the logging feature turned on.

       Selecting [[VV]] from PPRREEDDIICCTT''ss main menu will permit a ground station  to
       only predict passes for satellites that are potentially visible through
       optical means. Since all other passes are filtered out  in  this  mode,
       and  since  some satellites may never arrive over a ground station when
       optical viewing conditions  are  possible,  the  program  provides  the
       option  of  breaking  out of visual orbital prediction mode by pressing
       the [[EESSCC]]ape key as calculations are made. A prompt is displayed at the
       bottom of the screen to alert the user of this option.

       In  either  orbital  prediction mode, predictions will not be attempted
       for satellites that can never rise above the ground station's  horizon,
       or  for  satellites in geostationary orbits. If a satellite is in range
       at the starting date and time specified, PPRREEDDIICCTT will adjust the start-
       ing  date  back  in  time until the point of AOS so that the prediction
       screen displays the first pass in its entirety from start to finish.


SSIINNGGLLEE SSAATTEELLLLIITTEE TTRRAACCKKIINNGG MMOODDEE
       In addition to predicting satellite passes, PPRREEDDIICCTT  allows  satellites
       to  be  tracked  in real-time using PPRREEDDIICCTT''ss Single Satellite Tracking
       Mode (main menu option [[TT]]), or simultaneously as a group of  24  using
       the  program's  Multi-Satellite  Tracking  Mode (main menu option [[MM]]).
       The positions of the Sun and Moon  are  also  displayed  when  tracking
       satellites in real-time.

       Selecting  option  [[TT]]  from  PPRREEDDIICCTT''ss main menu places the program in
       Single Satellite Tracking Mode. The user will be prompted to select the
       satellite  of  interest,  after  which a screen will appear and display
       tracking positions for the satellite selected.

       In Single Satellite Tracking Mode, a wealth of information  related  to
       tracking a spacecraft and communicating through its transponder is dis-
       played.  The current date and time is displayed along with  the  satel-
       lite's sub-satellite point, its orbital altitude in both kilometers and
       statute miles, the slant range distance between the ground station  and
       the satellite in both kilometers and statute miles, the current azimuth
       and elevation headings toward the satellite, the  orbital  velocity  of
       the  satellite  in both kilometers per hour and statute miles per hour,
       the footprint of the satellite in both kilometers  and  statute  miles,
       the  modulo  256 orbital phase of the satellite, the eclipse depth, the
       spacecraft antenna squint angle, and orbital model in use, as  well  as
       the current orbit number are also displayed.  The date and time for the
       next AOS is also provided.

       Additionally, if the satellite is currently in range of the ground sta-
       tion,  the  amount  of Doppler shift experienced on uplink and downlink
       frequencies, path loss, propagation delay, and echo times are also dis-
       played.  The expected time of LOS is also provided.

       Uplink and downlink frequencies are held in PPRREEDDIICCTT''ss transponder data-
       base file _p_r_e_d_i_c_t_._d_b located under _$_H_O_M_E_/_._p_r_e_d_i_c_t.  A default  file  is
       provided with PPRREEDDIICCTT.

       Transponders  may  be selected by pressing the SPACE BAR.  The passband
       of the transponder may be tuned in 1 kHz increments by pressing  the  <<
       and  >> keys.  100 Hz tuning is possible using the ,, and .. keys.  (These
       are simply the << and >> keys without the SHIFT key.)

       If no transponder information is available, the data displayed  on  the
       tracking screen is abbreviated.

       The  features  available  in the Single Satellite Tracking Mode make it
       possible to accurately determine the proper uplink frequency to yield a
       given downlink frequency, or vice versa.  For example, if one wishes to
       communicate with a station heard  on  435.85200  MHz  via  FO-29,  then
       435.85200 MHz can be selected via the keyboard as an RX frequency using
       the tuning keys while tracking FO-29, and the corresponding ground sta-
       tion TX frequency will be displayed by PPRREEDDIICCTT.

       Obviously,  an  accurate  system  clock and up-to-date orbital data are
       required for the best tuning accuracy.

       If a sound card is present on your machine  and  the  Single  Satellite
       Tracking  Mode is invoked with an uppercase 'TT' rather than a lowercase
       'tt', PPRREEDDIICCTT will make periodic voice announcements stating the  satel-
       lite's tracking coordinates in real-time. Announcements such as:

       _"_T_h_i_s  _i_s _P_R_E_D_I_C_T_.  _S_a_t_e_l_l_i_t_e _i_s _a_t _f_i_f_t_y _s_i_x _d_e_g_r_e_e_s _a_z_i_m_u_t_h _a_n_d _f_o_r_t_y
       _f_i_v_e _d_e_g_r_e_e_s _e_l_e_v_a_t_i_o_n_, _a_n_d _i_s  _a_p_p_r_o_a_c_h_i_n_g_.   _S_a_t_e_l_l_i_t_e  _i_s  _c_u_r_r_e_n_t_l_y
       _v_i_s_i_b_l_e_._"

       are  made at intervals that are a function of how quickly the satellite
       is moving across the sky. Announcements  can  occur  as  frequently  as
       every  50 seconds for satellites in low earth orbits such as the Inter-
       national Space Station (370 km), or as infrequently as every 8  minutes
       for  satellites  in  very  high orbits, such as the AMC-6 geostationary
       satellite (35780 km). Voice announcements are performed  as  background
       processes  so  as  not  to  interfere with tracking calculations as the
       announcements are made. Alarms and special announcements are made  when
       the  satellite  being  tracked  enters  into or out of eclipse. Regular
       announcements can be forced by pressing the 'TT' key in Single Satellite
       Tracking Mode.


MMUULLTTII--SSAATTEELLLLIITTEE TTRRAACCKKIINNGG MMOODDEE
       Selecting  [[MM]]  from  PPRREEDDIICCTT''ss main menu places the program in a real-
       time multi-satellite tracking mode. In this mode, all 24 satellites  in
       the  program's database are tracked simultaneously along with the posi-
       tions of the Sun and Moon. Tracking data for  the  satellites  is  dis-
       played in two columns of 12 satellites each. The name, azimuth heading,
       elevation, sub-satellite point latitude (in degrees North)  and  longi-
       tude  (in  degrees  West)  positions are provided, along with the slant
       range distance between the satellite and the ground station (in kilome-
       ters).

       A letter displayed to the right of the slant range indicates the satel-
       lite's sunlight and eclipse conditions. If the satellite is  experienc-
       ing  an  eclipse period, an NN is displayed. If the satellite is in sun-
       light and the ground station is under the cover of  darkness,  a  VV  is
       displayed  to  indicate  the  possibility that the satellite is visible
       under the current conditions. If the satellite  is  in  sunlight  while
       conditions at the ground station do not allow the satellite to be seen,
       a DD is displayed.  Satellites in range of the ground station  are  dis-
       played  in  BBOOLLDD  lettering. The AOS dates and times for the next three
       satellites predicted to come into range are displayed on the bottom  of
       the  screen between the tracking coordinates of the Sun and Moon.  Pre-
       dictions are not made for satellites in  geostationary  orbits  or  for
       satellites  so  low  in inclination and/or altitude that they can never
       rise above the horizon of the ground station.


SSOOLLAARR IILLLLUUMMIINNAATTIIOONN PPRREEDDIICCTTIIOONNSS
       Selecting [[SS]] from PPRREEDDIICCTT''ss main menu will  allow  solar  illumination
       predictions to be made.  These predictions indicate how much sunlight a
       particular satellite will receive in a 24 hour period.   This  informa-
       tion  is  especially  valuable  to  spacecraft  designers and satellite
       ground station controllers who must monitor spacecraft power budgets or
       thermal  conditions  on-board  their  spacecraft  due  to  sunlight and
       eclipse periods.  It can even be used to predict the optimum times  for
       astronauts  to perform extra-vehicular activities in space. Solar illu-
       mination predictions may be logged to a file in the  same  manner  that
       orbital predictions may be logged (by pressing LL).


SSOOLLAARR AANNDD LLUUNNAARR OORRBBIITTAALL PPRREEDDIICCTTIIOONNSS
       In  addition  to  making orbital predictions of spacecraft, PPRREEDDIICCTT can
       also predict transits of  the Sun and the Moon.  Lunar predictions  are
       initiated by selecting [[LL]] from PPRREEDDIICCTT's Main Menu.  Solar predictions
       are selected through Main Menu option [[OO]].

       When making solar  and  lunar  orbital  predictions,  PPRREEDDIICCTT  provides
       azimuth  and  elevation  headings,  the  right  ascension, declination,
       Greenwich Hour Angle (GHA), radial velocity,  and  normalized  distance
       (range)  to the Sun or Moon.  Declination and Greenwich Hour Angle cor-
       respond to the latitude and longitude  of  the  object's  sub-satellite
       point  above  the  Earth's surface.  The radial velocity corresponds to
       the speed and direction the object is traveling toward (+) or away  (-)
       from  the  ground station, and is expressed in meters per second.  When
       the radial distance of the Moon is close to zero, the amount of Doppler
       shift experienced in Moonbounce communications is minimal.  The normal-
       ized distance corresponds to the object's actual distance to the ground
       station divided its average distance.  In practice, the normalized dis-
       tance can range from about 0.945 to 1.055 for the Moon, and about 0.983
       to 1.017 for the Sun.

       Note  that  the  effects of atmospherics are ignored in determining the
       elevation angles for the Sun and Moon. Furthermore, the  data  provided
       by  PPRREEDDIICCTT  corresponds  to  the object's center, and not the upper or
       lower limb, as is sometimes done when predicting the rising and setting
       times of these celestial objects.


OOPPEERRAATTIIOONN UUNNDDEERR TTHHEE XX--WWIINNDDOOWW SSYYSSTTEEMM
       PPRREEDDIICCTT may be run under the X-Window System by invoking it through the
       _x_p_r_e_d_i_c_t script contained with this software. _x_p_r_e_d_i_c_t can invoke _r_x_v_t,
       _x_t_e_r_m,  _E_t_e_r_m, _g_n_o_m_e_-_t_e_r_m_i_n_a_l, or _k_v_t, and display PPRREEDDIICCTT in a virtual
       terminal window.  _x_p_r_e_d_i_c_t should be edited for best results.  In  many
       cases, holding down the SHIFT key while pressing the plus (+) and minus
       (-) keys allows PPRREEDDIICCTT''ss window to  be  re-sized  when  started  under
       _x_p_r_e_d_i_c_t.


CCOOMMMMAANNDD LLIINNEE AARRGGUUMMEENNTTSS
       By  default,  PPRREEDDIICCTT  reads  ground  station location and orbital data
       information from a pair of files located in the user's  home  directory
       under  a  hidden  subdirectory  named _._p_r_e_d_i_c_t. Ground station location
       information is held in a file named  _p_r_e_d_i_c_t_._q_t_h,  while  orbital  data
       information for 24 satellites is held in a file named _p_r_e_d_i_c_t_._t_l_e.

       If  we wish to run PPRREEDDIICCTT using data from alternate sources instead of
       these default files, the names of such files may be passed  to  PPRREEDDIICCTT
       on  the  command  line  when the program is started. For example, if we
       wish to read the TLE file _v_i_s_u_a_l_._t_l_e and the QTH  file  _b_e_a_c_h___h_o_u_s_e_._q_t_h
       rather  than  the  default  files,  we could start PPRREEDDIICCTT and pass the
       names of these alternate files to the program in the following manner:

            _p_r_e_d_i_c_t _-_t _v_i_s_u_a_l_._t_l_e _-_q _b_e_a_c_h___h_o_u_s_e_._q_t_h

       or

            _p_r_e_d_i_c_t _-_q _b_e_a_c_h___h_o_u_s_e_._q_t_h _-_t _v_i_s_u_a_l_._t_l_e

       If the files specified are not located in the  current  working  direc-
       tory,  then  their  relative or absolute paths should also be specified
       along with their names (_p_r_e_d_i_c_t _-_t _/_h_o_m_e_/_k_d_2_b_d_/_o_r_b_s_/_v_i_s_u_a_l_._t_l_e).

       It is also possible to specify only one alternate file while using  the
       default for the other. For example,

            _p_r_e_d_i_c_t _-_t _v_i_s_u_a_l_._t_l_e

       reads QTH information from the default _~_/_._p_r_e_d_i_c_t_/_p_r_e_d_i_c_t_._q_t_h location,
       and TLE information from _v_i_s_u_a_l_._t_l_e, while

            _p_r_e_d_i_c_t _-_q _b_o_b_s_._q_t_h

       reads QTH information  from  _b_o_b_s_._q_t_h  and  TLE  information  from  the
       default _~_/_._p_r_e_d_i_c_t_/_p_r_e_d_i_c_t_._t_l_e location.


QQUUIIEETT OORRBBIITTAALL DDAATTAABBAASSEE UUPPDDAATTEESS
       It  is  also  possible  to  update PPRREEDDIICCTT''ss satellite orbital database
       using another command line option that updates the database from a NASA
       two-line  element data set. PPRREEDDIICCTT then quietly exits without display-
       ing anything to the screen, thereby eliminating the need  for  entering
       the  program and selecting the appropriate menu options. This option is
       invoked using the _-_u command line switch as follows:

            _p_r_e_d_i_c_t _-_u _o_r_b_s_2_4_8_._t_l_e

       This example updates PPRREEDDIICCTT''ss default orbital database with the Keple-
       rian  elements  found  in  the file _o_r_b_s_2_4_8_._t_l_e. PPRREEDDIICCTT may be updated
       from a list of files as well:

            _p_r_e_d_i_c_t _-_u _a_m_a_t_e_u_r_._t_l_e _v_i_s_u_a_l_._t_l_e _w_e_a_t_h_e_r_._t_l_e

       If an alternate datafile requires updating, it may also be specified on
       the command line using the _-_t switch as follows:

            _p_r_e_d_i_c_t _-_t _o_s_c_a_r_._t_l_e _-_u _a_m_a_t_e_u_r_._t_l_e

       This  example  updates the _o_s_c_a_r_._t_l_e orbital database with the two-line
       element data contained in _a_m_a_t_e_u_r_._t_l_e.

       These options permit the automatic update  of  PPRREEDDIICCTT''ss  orbital  data
       files  using  Keplerian  orbital  data obtained through automatic means
       such as FTP, HTTP, or pacsat satellite download.

       For example, the following script  can  be  used  to  update  PPRREEDDIICCTT''ss
       orbital database via the Internet:

          #!/bin/sh
          wget -qr www.celestrak.com/NORAD/elements/amateur.txt -O amateur.txt
          wget -qr www.celestrak.com/NORAD/elements/visual.txt -O visual.txt
          wget -qr www.celestrak.com/NORAD/elements/weather.txt -O weather.txt
          /usr/local/bin/predict -u amateur.txt visual.txt weather.txt

       To  truly  automate the process of updating your orbital database, save
       the above commands to a file in your home  directory  (such  as  _k_e_p_u_p_-
       _d_a_t_e),  and  add the following line to your crontab (type _c_r_o_n_t_a_b _-_e to
       edit your crontab):

            _0 _2 _* _* _* _k_e_p_u_p_d_a_t_e

       and PPRREEDDIICCTT will automatically update its database every  day  at  2:00
       AM.


AAUUTTOOMMAATTIICC AANNTTEENNNNAA TTRRAACCKKIINNGG
       PPRREEDDIICCTT  is compatible with serial port antenna rotator interfaces con-
       forming to  the  EasyComm  2  protocol  standard.   This  includes  the
       PIC/TRACK interface developed by Vicenzo Mezzalira, IW3FOL <http://dig-
       ilander.iol.it/iw3fol/pictrack.html>, TAPR's EasyTrak  Jr.   (currently
       under  development),  and  Suding  Associates  Incorporated's Dish Con-
       trollers  <http://www.ultimatecharger.com/Dish_Controllers.html>.   The
       FODTRACK  rotator  interface is supported through the use of Luc Lange-
       hegermann's (LX1GT) ffooddttrraacckk utility written for and included with PPRREE--
       DDIICCTT.

       Using  any of these hardware interfaces, PPRREEDDIICCTT can automatically con-
       trol the position of AZ/EL antenna rotators, and  keep  antennas  accu-
       rately  pointed toward a satellite being tracked by PPRREEDDIICCTT.  In opera-
       tion, tracking data from PPRREEDDIICCTT is directed to  the  specified  serial
       port using the _-_a command line option.  For example:

            _p_r_e_d_i_c_t _-_a _/_d_e_v_/_t_t_y_S_0

       will send AZ/EL tracking data to the first serial port when the program
       is tracking a satellite in the Single  Satellite  Tracking  Mode.   The
       data  sent to the serial port is of the form: _A_Z_2_4_1_._0 _E_L_2_6_._0 using 9600
       baud, 8-data bits, 1-stop bit, no parity, and no handshaking.  Data  is
       sent  to  the  interface if the azimuth or elevation headings change by
       one degree or more.  For  interfaces  requiring  keepalive  updates  at
       least  once  per  second whether the AZ/EL headings have changed or not
       (such as the ones by SAI), the _-_a_1 option may be used:

            _p_r_e_d_i_c_t _-_a_1 _/_d_e_v_/_t_t_y_S_0


AADDDDIITTIIOONNAALL OOPPTTIIOONNSS
       The _-_f command-line option, when followed by a satellite name or object
       number and starting date/time, allows PPRREEDDIICCTT to respond with satellite
       positional information.  This feature  allows  PPRREEDDIICCTT  to  be  invoked
       within  other  applications  that  need  to determine the location of a
       satellite at a particular point in time, such as the location of  where
       a  CCD  camera image was taken by a Pacsat satellite based on its time-
       stamp.

       The information produced includes the date/time  in  Unix  format  (the
       number of seconds since midnight UTC on January 1, 1970), the date/time
       in ASCII (UTC), the elevation of the satellite in degrees, the  azimuth
       heading  of the satellite, the orbital phase (modulo 256), the latitude
       and longitude of the satellite's sub-satellite point at the time speci-
       fied,  the  slant  range to the satellite in kilometers with respect to
       the ground station's location, the orbit number, and  the  spacecraft's
       sunlight visibility information.

       The date/time must be specified in Unix format (number of seconds since
       midnight UTC on January 1, 1970).  If no starting  or  ending  time  is
       specified, the current date/time is assumed and a single line of output
       is produced.  If a starting and ending time are specified,  a  list  of
       coordinates  beginning  at  the  starting time/date and ending with the
       ending time/date will be returned by the program with a one second res-
       olution.  If the letter _m is appended to the ending time/date, then the
       data returned by the program will have a one minute resolution.  The _-_o
       option  allows  the  program  to write the calculated data to an output
       file rather than directing it to the standard output device if desired.

       The proper syntax for this option is as follows:

            _p_r_e_d_i_c_t _-_f _I_S_S _9_7_7_4_4_6_3_9_0 _9_7_7_4_4_6_4_0_0 _-_o _d_a_t_a_f_i_l_e

       A list of coordinates starting at the current date/time and  ending  10
       seconds later may be produced by the following command:

            _p_r_e_d_i_c_t _-_f _I_S_S _+_1_0

       If a list of coordinates specifying the position of the satellite every
       minute for the next 10 minutes is desired, the following command may be
       used:

            _p_r_e_d_i_c_t _-_f _I_S_S _+_1_0_m

       If  a  satellite  name  contains  spaces,  then the entire name must be
       enclosed by "quotes".

       The _-_p option allows orbital predictions for a single pass to be gener-
       ated by PPRREEDDIICCTT via the command-line.  For example:

            _p_r_e_d_i_c_t _-_p _O_S_C_A_R_-_1_1 _1_0_0_3_5_3_6_7_6_7

       starts  predictions  for  the  OSCAR-11  satellite  at  a  Unix time of
       1003536767 (Sat 20Oct01 00:12:47 UTC).  If the  starting  date/time  is
       omitted,  the  current  date/time  is  used.   If  a pass is already in
       progress at the starting date/time specified, orbital  predictions  are
       moved  back  to  the beginning of AOS of the current pass, and data for
       the entire pass from AOS to LOS is provided.

       When either the _-_f or _-_p options are used, PPRREEDDIICCTT produces  an  output
       consisting  of the date/time in Unix format, the date and time in ASCII
       (UTC), the elevation of the satellite in degrees, the  azimuth  of  the
       satellite  in degrees, the orbital phase (modulo 256), the latitude (N)
       and longitude (W) of the satellite's  sub-satellite  point,  the  slant
       range  to  the  satellite  (in  kilometers),  the orbit number, and the
       spacecraft's sunlight visibility information.  For example:  1003611710
       Sat  20Oct01 21:01:50   11    6  164   51   72   1389  16669 * The out-
       put isn't annotated, but then again, it's meant to  be  read  by  other
       software.

       The _-_d_p option produces a quick orbital prediction for the next pass of
       a specified satellite, including 100 MHz downlink Doppler shift  infor-
       mation, in CSV format.  For example:

            _p_r_e_d_i_c_t _-_d_p _I_S_S

       produces:

       1525500165,Sat 05May18 06:02:45,701.256856
       1525500169,Sat 05May18 06:02:49,678.755942
       1525500172,Sat 05May18 06:02:52,656.033048
       1525500176,Sat 05May18 06:02:56,633.093151
       1525500179,Sat 05May18 06:02:59,609.940999
       1525500183,Sat 05May18 06:03:03,586.582443
       1525500186,Sat 05May18 06:03:06,563.022553
       <... output trimmed ...>
       1525500367,Sat 05May18 06:06:07,-733.663728
       1525500370,Sat 05May18 06:06:10,-755.793182
       1525500374,Sat 05May18 06:06:14,-777.690366
       1525500377,Sat 05May18 06:06:17,-799.351435
       1525500381,Sat 05May18 06:06:21,-820.773340
       1525500384,Sat 05May18 06:06:24,-841.952820
       1525500388,Sat 05May18 06:06:28,-862.887147


       where  the Unix time is followed by the UTC date/time and 100 MHz down-
       link-referenced Doppler shift.  The satellite name can be followed by a
       starting date/time and ending date/time much like the _-_f option.


SSEERRVVEERR MMOODDEE
       PPRREEDDIICCTT''ss  network  socket interface allows the program to operate as a
       server capable of providing tracking  data  and  other  information  to
       client  applications  using  the  UDP protocol.  It is even possible to
       have the PPRREEDDIICCTT server and client  applications  running  on  separate
       machines  provided  the  clients  are connected to the server through a
       functioning network connection.

       The _-_s switch is used to start PPRREEDDIICCTT in server mode:

            _p_r_e_d_i_c_t _-_s

       By default, PPRREEDDIICCTT uses socket port 1210 for communicating with client
       applications.   Therefore,  the following line needs to be added to the
       end your _/_e_t_c_/_s_e_r_v_i_c_e_s file:

            _p_r_e_d_i_c_t   _1_2_1_0_/_u_d_p

       The port number (1210) can be changed to  something  else  if  desired.
       There  is  no  need  to recompile the program if it is changed.  To run
       more than one instance of PPRREEDDIICCTT in server mode on a single  host,  an
       alternate port must be specified when invoking the additional instances
       of PPRREEDDIICCTT.  This can be accomplished by using the _-_n switch:

            _p_r_e_d_i_c_t _-_n _1_2_1_1 _-_t _o_t_h_e_r___t_l_e___f_i_l_e _-_s

       When invoked in server mode, PPRREEDDIICCTT immediately enters Multi-Satellite
       Tracking  Mode,  and  makes  live  tracking  data available to clients.
       Clients may poll PPRREEDDIICCTT for tracking data when the program is  running
       in  either the Multi-Satellite or Single Satellite Tracking Mode.  When
       in Multi-Satellite Tracking mode, tracking  data  for  any  of  the  24
       satellites in the program's database may be accessed by client applica-
       tions.  When in Single-Satellite Tracking mode, only live tracking data
       for  the single satellite being tracked may be accessed.  Either track-
       ing mode may be ended at any time.  When this  is  done,  PPRREEDDIICCTT  will
       return the last calculated satellite tracking data until the program is
       again put into a real-time tracking mode.   This  allows  the  user  to
       return  to the main menu, and use other features of the program without
       sending potentially harmful data to client applications.

       The best way to write a client application is to use the  demonstration
       program  (demo.c)  included in this distribution of PPRREEDDIICCTT as a guide.
       The sample program has comments to explain how each component operates.
       It  is useful to pipe the output of this program through _l_e_s_s to easily
       browse through the data returned (_d_e_m_o _| _l_e_s_s).

       In operation, a character array is filled with the  command  and  argu-
       ments  to  be sent to PPRREEDDIICCTT.  A socket connection is then opened, the
       request is sent, a response is received, and the socket  connection  is
       closed.  The command and arguments are in ASCII text format.

       Several  excellent  network  client  applications  are included in this
       release of PPRREEDDIICCTT, and may be found under the  _p_r_e_d_i_c_t_/_c_l_i_e_n_t_s  direc-
       tory.


AADDDDIINNGG SSAATTEELLLLIITTEESS
       One  of  the  most frequently asked questions is how satellites in PPRREE--
       DDIICCTT''ss orbital database may be added, modified,  or  replaced.   As  it
       turns  out, there are several ways in which this can be done.  Probably
       the easiest is to manually edit your _~_/_._p_r_e_d_i_c_t_/_p_r_e_d_i_c_t_._t_l_e  file,  and
       replace  an  existing  satellite's entry with 2-line Keplerian data for
       the new satellite.  If this method is chosen, however, just  make  sure
       to include ONLY the two line data, and nothing else.

       Another way is to is select the Keyboard Edit option from the program's
       Main Menu, select a satellite you wish to replace.  Edit the  name  and
       object number (replacing the old information with the new information).
       Just hit ENTER, and accept all the other orbital parameters shown.  Get
       back  to  PPRREEDDIICCTT''ss  Main Menu.  Select Auto Update, and then enter the
       filename containing the 2-line  element  data  for  your  favorite  new
       satellite.   The  new satellite data should be detected by PPRREEDDIICCTT, and
       the orbital data for the old satellite will be overwritten by  the  new
       data.


NNEEAATT TTRRIICCKKSS
       In  addition  to  tracking and predicting passes of satellites, PPRREEDDIICCTT
       may also be used to generate a NASA two-line Keplerian element data set
       from data entered via keyboard. For example, let's say you're listening
       to Space Shuttle audio re-broadcasts via WA3NAN and Keplerian  elements
       for  the  Space Shuttle's orbit are given by the announcer. The orbital
       data provided by WA3NAN in verbal form may  be  manually  entered  into
       PPRREEDDIICCTT''ss  orbital database using option [[EE]] of the program's main menu
       (Keyboard Edit of Orbital Database). The orbital  data  for  the  Space
       Shuttle in NASA two-line element form can then be found in your orbital
       database file, and may imported to any other satellite tracking program
       that accepts two-line element files or distributed to others electroni-
       cally.

       It is also possible to run PPRREEDDIICCTT as a background process  and  direct
       its  display  to  an unused virtual console by using the following com-
       mand:

               _p_r_e_d_i_c_t _< _/_d_e_v_/_t_t_y_8 _> _/_d_e_v_/_t_t_y_8 _&

       Switching to virtual console number 8 (ALT-F8 in text mode) will  allow
       PPRREEDDIICCTT  to  be  controlled and displayed even after you've logged out.
       This is especially handy when running  PPRREEDDIICCTT  in  server  mode  on  a
       remote machine.


GGLLOOSSSSAARRYY OOFF TTEERRMMSS
       The  following  terms are frequently used in association with satellite
       communications and space technology:


AAOOSS::
       Acquisition of Signal - the  time  at  which  a  ground  station  first
       acquires  radio  signals  from  a satellite. PPRREEDDIICCTT defines AOS as the
       time when the satellite being tracked comes within +/- 0.03 degrees  of
       the local horizon, although it may have to rise higher than this before
       signals are first heard.

AAppooggeeee::
       Point in a satellite's orbit when the satellite is at its farthest dis-
       tance from the earth's surface.

AAnnoommaalliissttiicc PPeerriioodd::
       A  satellite  orbital  parameter specifying the time between successive
       perigees.

AAsscceennddiinngg NNooddee::
       Point in a satellite's orbit when its sub-satellite point  crosses  the
       equator moving south to north.

AAzziimmuutthh::
       The  compass  direction  measured clockwise from true north.  North = 0
       degrees, East = 90 degrees,  South  =  180  degrees,  and  West  =  270
       degrees.

DDeesscceennddiinngg NNooddee::
       Point  in  a satellite's orbit when its sub-satellite point crosses the
       equator moving north to south.

DDoopppplleerr SShhiifftt::
       The motion of a satellite in its orbit around the earth,  and  in  many
       cases  the  rotational motion of the earth itself, causes radio signals
       generated by satellites to be received on Earth at frequencies slightly
       different  than  those upon which they were transmitted. PPRREEDDIICCTT calcu-
       lates what effect these motions have upon the reception  of  satellites
       transmitting on the 146 MHz and 435 MHz Amateur Radio bands.

EElleevvaattiioonn::
       The  angle between the local horizon and the position of the satellite.
       A satellite that appears directly above a particular location  is  said
       to be located at an elevation of 90 degrees. A satellite located on the
       horizon of a particular location is said to be located at an  elevation
       of 0 degrees.  A satellite with an elevation of less than zero is posi-
       tioned below the local horizon, and radio communication with  a  satel-
       lite in such a position is not possible under normal circumstances.

FFoooottpprriinntt::
       Diameter  of  the Earth's surface visible from a satellite.  The higher
       the satellite's orbital altitude, the greater the  footprint,  and  the
       wider the satellite's communications coverage.

LLOOSS::
       Loss of Signal - the time at which a ground station loses radio contact
       with a satellite. PPRREEDDIICCTT defines LOS as the time  when  the  satellite
       being tracked comes within +/- 0.03 degrees of the local horizon.

OOrrbbiittaall PPhhaassee::
       An  orbital  "clock" that describes a satellite's orbital position with
       respect to perigee. Orbital Phase may be modulo 256, or modulo 360, and
       is sometimes referred to as mean anomaly when speaking of amateur radio
       satellites in elliptical  orbits,  such  as  the  Phase  3  satellites.
       Orbital phase is zero at perigee.

PPaatthh LLoossss::
       The apparent attenuation a radio signal undergoes as it travels a given
       distance. This attenuation is the result of the dispersion radio  waves
       experience  as  they  propagate  between transmitter and receiver using
       antennas of finite gain. Free space path loss is  technically  an  oxy-
       moron since free space is loss free.

PPeerriiggeeee::
       Point  in a satellite's orbit when the satellite is at its closest dis-
       tance to the earth's surface.

NNooddaall PPeerriioodd::
       A satellite orbital parameter specifying the  time  between  successive
       ascending nodes.

SSllaanntt RRaannggee::
       The straight line distance between the ground station and the satellite
       at a given time.

SSuubb--SSaatteelllliittee PPooiinntt::
       The latitude and longitude specifying the location on the Earth that is
       directly below the satellite.


AADDDDIITTIIOONNAALL IINNFFOORRMMAATTIIOONN
       Detailed  information  on  the  operation of PPRREEDDIICCTT''ss UDP socket-based
       interface as well as sample code for writing your own  client  applica-
       tions  is  available  in the _p_r_e_d_i_c_t_/_c_l_i_e_n_t_s_/_s_a_m_p_l_e_s subdirectory.  The
       latest news is available through the official PPRREEDDIICCTT software web page
       located at: <http://www.qsl.net/kd2bd/predict.html>.

FFIILLEESS
       ~/.predict/predict.tle
              Default database of orbital data

       ~/.predict/predict.db
              Satellite transponder database file

       ~/.predict/predict.qth
              Default ground station location information


AAUUTTHHOORRSS
       PPRREEDDIICCTT  was  written  by  John A. Magliacane, KD2BD <kd2bd@amsat.org>.
       The  socket  server  code  was  contributed  by  Ivan  Galysh,   KD4HBO
       <galysh@juno.nrl.navy.mil>.   The PIC/TRACK serial port antenna rotator
       controller code was contributed  by  Vittorio  Benvenuti,  I3VFJ  <ben-
       scosm@iol.it>.  SGP4/SDP4 code was derived from Pacsal routines written
       by Dr. T.S. Kelso, and converted to 'C'  by  Neoklis  Kyriazis,  5B4AZ.
       See the CREDITS file for additional information.




KD2BD Software                    05 May 2018                       PREDICT(1)
